This invention relates to mineral spirits and more particularly to the reclamation of contaminated mineral spirits.
Organic solvents have become commonplace in Department of Defense (DOD) installations for the removal of grease, dirt, and other contaminants from metal surfaces. The widely accepted methods of disposal have been incineration and deep well injection but, as a result of increasingly strict pollution regulations and the rising cost of solvents, the DOD has been directed to investigate recycling rather than disposal.
In one application, 92.3 percent mineral spirits (Federal Specification TT-T-291 Type III) and 7.7 percent preservative oil (WS 12953, TECTYL Q1449A) are used in cleaning baths as part of a postrun maintenance operation for torpedoes. As torpedoes pass through these cleaning baths, grease and dirt as well as Otto Fuel II (torpedo propellant) and hydrogen cyanide (HCN), a combustion product of Otto Fuel II, accumulate. Otto Fuel II is composed of 76 weight percent of 1,2-propanediol dinitrate (PGDN), 22.5 weight percent of dibutyl sebecate (that is dibutyl decanedioate), and 1.5 weight percent of 2-nitrodiphenylamine. Simple distillation produces a mineral spirit distillate which is still contaminated with 1,2-propanediol dinitrate and hydrogen cyanide. A process for recovering the mineral spirits free of Otto Fuel II and hydrogen cyanide is needed. Preferably such a process should not require chemical reagents.